用非表面强化方法提高铸态球铁曲轴的可靠性

An Experiment on Using Non-Surface-Strengthening Method to Increase Reliability of As-Cast Nodular Iron Crankshaft

在不采用圆角滚压等表面强化处理的条件下,为使铸态球铁曲轴的弯曲疲劳强度和耐磨性达到技术要求,采取了三个措施:(1)通过合金化和优化铸造工艺,使强度和韧性达到最佳匹配;(2)加大连杆轴颈与曲柄臂的过度圆角;(3)增大曲柄臂的厚度。曲轴弯曲疲劳强度对比试验和300h台架可靠性试验以及25000km道路试验均证明,采用上述措施制造铸态球铁曲轴的方案既降低曲轴成本,又能使曲轴具有足够的弯曲疲劳强度。

Without using surface-strengthening treatments such as round corner rolling,three measures was adopted to make the bending fatigue strength and wear resistance of the nodular iron crankshaft to meet their thechnical requirements:(1)obtain the optimum match of strength and toughness by alloying and optimizing foundry processes;(2)enlarge the round corners between the conrod shaft necks and the crank arms ;(3)increase thickness of the crank arms.The comparative bendintg fatigue test,300hrs bench running reliability test and25000km driving reliability test have showed that adopting above mentioned measures to produce as-cast nodular iron crankshaft is a practical scheme which not only reduced production cost,also made the crankshaft to be of sufficient bending fatigue strength.